Can Radiation Losses Be Recovered in Nuclear Fusion for Net Power Gain?

[TESL@]

Hello,

After researching on many kinds of confinement methods and most promising reactions, (aneutronic fusion etc.) I saw almost every paper complained about radiation losses as the greatest problem preventing net power gain. And except Tri-Alpha Energy and LPP (Dense Plasma Focus) companies, nobody seems to be caring about recovering these losses. Since degenerate plasma is not practical aside from inertial confinement, the radiation must either be harvested or sent back to the plasma. So, why don't they just generate electricity from electron cyclotron waves by a rectenna array, and in return heat the ions by ICRH? What about bremsstrahlung? Is there no possibility but inefficient photoelectric converters?

Thank you.

 

[mfb]

So, why don't they just generate electricity from electron cyclotron waves by a rectenna array

The radiation is not coherent, and I don't think radio waves make up a significant part of the emitted power.

The harsh radiation and temperature conditions also limit the number of things you can place next to the plasma. It is hard enough to find some material for the first wall, even without additional functionality.

 

[TESL@]

Thank you for replying. Anything about bremsstrahlung?

edit: Inverse-bremsstrahlung is possible http://link.springer.com/chapter/10.1007/978-1-4684-8416-8_20

 

[the_wolfman]

After researching on many kinds of confinement methods and most promising reactions, (aneutronic fusion etc.) I saw almost every paper complained about radiation losses as the greatest problem preventing net power gain. And except Tri-Alpha Energy and LPP (Dense Plasma Focus) companies, nobody seems to be caring about recovering these losses. Since degenerate plasma is not practical aside from inertial confinement, the radiation must either be harvested or sent back to the plasma. So, why don't they just generate electricity from electron cyclotron waves by a rectenna array, and in return heat the ions by ICRH? What about bremsstrahlung? Is there no possibility but inefficient photoelectric converters?

Both Tri-alpha and Lpp are interested in p-B fusion. p-B fusion requires orders of magnitude hotter temperatures than D-T fusion. The power radiated by Bremsstrahlung increases with both temperature and ion charge. For p-B fusion Bremsstrahlung is a potential show stopper for p-B fusion. Its a huge issue!

In a burning D-T plasma, 80% of the energy is lost via the neutron. This is the lions share of the energy, and the focus should be on capturing this energy efficiently (neutrons are also important because they are used to breed tritium). The remaining 20% of the energy is lost via various conduction, convection, and radiation mechanisms. I expect that various turbulant losses will dominate the remaining 20%. Turbulance dominates the heat loss in modern high performance tokamaks and stellarators.

 

[alphy]

Thank you for your question. I understand the concern about radiation losses in nuclear fusion and the importance of finding ways to recover them in order to achieve net power gain. There are ongoing research efforts to address this issue, and I would like to provide some insights on possible solutions.

Firstly, it is important to note that radiation losses in fusion occur due to different mechanisms, such as bremsstrahlung and line radiation, and they vary depending on the specific fusion reaction and confinement method being used. Therefore, the approach to recovering these losses may also differ. For example, in the case of aneutronic fusion reactions, electron cyclotron waves can be used to efficiently convert the radiation into electricity through a rectenna array, as you mentioned. However, this may not be applicable for other types of fusion reactions.

In addition, recovering radiation losses in fusion is a complex and challenging task as it involves controlling and manipulating high-energy particles and radiation in a confined plasma. This requires advanced technologies and techniques, which are still being developed and improved. Therefore, it is not surprising that not all companies or research groups are actively working on this aspect of fusion research.

Furthermore, in order to achieve net power gain in fusion, it is not only important to recover radiation losses, but also to minimize them in the first place. This can be achieved through better confinement methods, such as the use of magnetic fields or inertial confinement, as you mentioned. These methods can help reduce the amount of radiation produced during the fusion process.

In conclusion, recovering radiation losses in nuclear fusion for net power gain is a complex and ongoing research topic. While there are some promising solutions being explored, it is still a challenging task that requires further research and development. I hope this response has provided some insights on the current state of research in this area. Thank you.